Sun protection is an important practice for maintaining skin health, safeguarding against sunburn and long-term damage from ultraviolet (UV) radiation. There are two primary categories of sunscreens available: chemical and mineral. Chemical sunscreens operate by absorbing UV rays, transforming them into heat, which then dissipates from the skin. In contrast, mineral sunscreens create a physical barrier on the skin’s surface to reflect UV light. While both types offer protection, specific concerns have emerged regarding the use of chemical sunscreens, particularly during pregnancy.
Key Ingredients in Chemical Sunscreen
Chemical sunscreens typically contain a blend of active organic compounds designed to interact with UV light. Common ingredients include oxybenzone, avobenzone, octinoxate, octisalate, homosalate, and octocrylene.
Many chemical sunscreens combine several of these ingredients to achieve broad-spectrum protection against both UVA and UVB rays. For instance, octocrylene is often included to stabilize other active ingredients like avobenzone, enhancing the sunscreen’s effectiveness over time. While these ingredients are effective at blocking UV light, their interaction with the body differs significantly from mineral alternatives.
How Chemical Sunscreen Ingredients Affect the Body
Unlike mineral sunscreens, which largely remain on the skin’s surface, the active ingredients in chemical sunscreens are designed to be absorbed. Studies have confirmed that these ingredients are absorbed through the skin and enter the bloodstream. This absorption can occur after a single application, with some chemicals detectable in the blood for days or even weeks afterward. For example, blood concentrations of oxybenzone have been found to exceed proposed FDA safety thresholds after just one day of use.
Once absorbed, some of these chemical UV filters can act as endocrine disruptors. Endocrine disruptors are substances that can interfere with the body’s natural hormone systems, potentially mimicking or blocking the actions of hormones like estrogen, testosterone, or thyroid hormones. This systemic exposure and potential for hormonal interference raise considerations for overall health.
Potential Risks During Pregnancy
The systemic absorption and endocrine-disrupting properties of chemical sunscreen ingredients present specific considerations during pregnancy. A developing fetus is particularly sensitive to hormonal fluctuations, as hormones play a crucial role in organ formation and overall development. Chemical UV filters, being able to cross the placental barrier, can expose the fetus to these compounds.
Exposure to certain chemical sunscreen ingredients has been linked to potential adverse outcomes. For example, oxybenzone has been associated with altered birth weight, specifically lower birth weights in baby girls when mothers were exposed during pregnancy. Some research also suggests a link between oxybenzone exposure and Hirschsprung’s disease, a rare birth defect affecting the large intestine. Furthermore, trace amounts of chemicals like oxybenzone, octinoxate, and homosalate have been detected in breast milk, indicating potential transfer to the infant after birth. The interference with maternal hormonal balance, which is vital for a healthy pregnancy, is another area of concern.
Safer Sun Protection Choices
Given the concerns associated with chemical sunscreens during pregnancy, other sun protection methods are often suggested. Mineral sunscreens, which contain zinc oxide and titanium dioxide as active ingredients, are generally considered a preferred alternative. This mechanism means they are minimally absorbed into the bloodstream.
Beyond sunscreen, other non-chemical strategies contribute to comprehensive sun protection. Seeking shade, especially during peak sun hours, typically between 10 AM and 4 PM, can significantly reduce UV exposure. Wearing protective clothing, such as long-sleeved shirts, pants, and wide-brimmed hats, also provides an effective physical barrier against the sun’s rays. Combining these practices offers a robust approach to sun safety.